The present invention relates to a brushless DC linear motor.
A brushless DC linear motor can send the current to coils without a brush. Therefore, it has such advantages that it is not accompanied by abrasion of brush part nor maintenance works, such as a change of a brush, and has no such bad effect upon electronic equipments as electric noises do generating when a brush switching the current. Thus, several suggestions have been made, as shown, for example, in Jpn. examined publication No. Toku-Ko-Sho 59-1061, and 61-24907 and the like.
Nevertheless, there are no brushless DC linear motor so far in use which has a coil unit comprising a set of three flat coils of the same shape containing an empty core section and a winding section and corresponding to a magnet body wherein several isometric magnets are arranged to alternate their magnetizing directions and put their magnetic pole-faces in a row in a perpendicular direction to this magnetizing direction. Moreover, it leaves more to be desired. Even in the case that the dimension of an empty core section and a winding section of flat coils and the mutual positional relationship among the three flat coils are precisely prescribed in reference to a magnetic pole-pitch of the magnet body and, further, the mutual positional relationship of three sensors detecting the relative relationship between the magnet body and the coil unit is prescribed in reference to the magnetic pole-pitch of the magnet body and the positional relationship between this sensor and the coil unit is specified, and a coil unit comprising a set of three flat coils is added to increase the thrust with the electric flow terminals of the three flat coils connected with a delta connection or a star connection, an additional sensor may be unnecessary to operate it. And in the case that a coil unit is added as aforementioned, only three wires connected to the three terminals of the delta connection or star connection may be necessary as the wiring to send the current.